Reirradiation for diffuse intrinsic pontine glioma: a systematic review and meta-analysis.

BACKGROUND: Diffuse intrinsic pontine glioma (DIPG) is a pediatric brain tumor with dismal prognosis despite initial radiation therapy (RT). The clinical consequences of attempting reirradiation (reRT) in these patients to alleviate both symptomatology and improve prognosis are currently unclear. Thus, the aim of this systematic review and meta-analysis was to clarify the efficacy and safety of reRT in DIPG. METHODS: Searches of seven electronic databases from inception to January 2019 were conducted following the appropriate guidelines. Articles were screened against prespecified criteria. The incidence and duration of clinical outcomes were then extracted and pooled by means of meta-analysis from the included studies. RESULTS: A total of 7 studies satisfied all criteria, describing 90 cases of DIPG in which reRT was attempted 11.8-14 months after initial RT. Based on a random-effects model, the incidences of clinical improvement and radiologic response following reRT were 87% (95% CI, 78-95%) and 69% (95% CI, 52-84%), respectively. The incidence of acute serious toxicity was 0% (95% CI, 0-4%). Pooled overall survivals from initial diagnosis and time of reRT were 18.0 months (95% CI, 14.2-21.7) and 6.2 months (95% CI, 5.5-7.0), respectively. CONCLUSIONS: Based on these results, the clinical consequences of reRT for DIPG when administered appropriately and safely at first progression appear acceptable, and potentially favorable, based on the limited evidence in the current literature. Concerns regarding acute serious toxicity were not realized. It is likely that a subcohort of all DIPG diagnoses will be most amenable to improve prognosis with reRT, and greater investigation is required to identify their characteristics.

Re-irradiation volumetric modulated arc therapy optimization based on cumulative biologically effective dose objectives.

The objective of this note is to introduce a clinical tool that generates ideal base plan dose distributions to enable re-irradiation volumetric modulated arc therapy (VMAT) optimization based on cumulative biological effective dose objectives for specific organs at risk (OARs). The tool is demonstrated with a lung cancer case that required re-irradiation at our clinic. First, previous treatment dose is deformed onto the retreatment computed tomography (CT) using commercial software. Then, the in-house Matlab tool alters the deformed previous dose using radiobiological concepts on a voxel-by-voxel manner to generate an ideal base plan dose distribution. Ideal base plans that were generated using the in-house Matlab tool were compatible with the Varian Eclipse™ treatment planning system. The tool enabled optimization of VMAT re-irradiation plans using cumulative dose limits for OARs and all OAR cumulative dose objectives were met on the first optimization for the recurrent lung cancer case tested.

Policies for reirradiation of recurrent high-grade gliomas: a survey among Italian radiation oncologists.

PURPOSE: To assess the contribution of Italian radiation oncologists in the current management of recurrent high-grade gliomas (HGG), focusing on a reirradiation (reRT) approach. METHODS: In 2015, the Reirradiation and the Central Nervous System Study Groups on behalf of the Italian Association of Radiation Oncology (AIRO) proposed a survey. All Italian radiation oncologists were individually invited to complete an online questionnaire regarding their clinical management of recurrent HGG, focusing on a reRT approach. RESULTS: A total of 37 of 210 questionnaires were returned (18% of all centers): 16 (43%) from nonacademic hospitals, 14 (38%) from academic hospitals, 5 (13%) from private institutions, and 2 (6%) from hadron therapy centers. The majority of responding centers (59%) treated ≤5 cases per year. Performance status at the time of recurrence, along with a target diameter <5 cm and an interval from primary radiation ≥6 months, were the prevalent predictive factors considered for reRT. Sixty percent of reirradiated patients had already received a salvage therapy, either chemotherapy (40%) or reoperation (20%). The most common approach for reRT was fractionated stereotactic radiotherapy to a mean (photon) dose of 41.6 Gy. CONCLUSIONS: Although there were wide variations in the clinical practice of reRT across the 37 centers, the core activities were reasonably consistent. These findings provide a basis for encouraging a national collaborative study to develop, implement, and monitor the use of reRT in this challenging clinical setting.